As disclosed, e.g., in U.S. Pat. Nos. 3,244,758 (Eberhardt) and 4,179,580 (Cobb) and in European Patent No.128001 (Kudoh et al.), it is known that supported alkali metals, including potassium and sodium-potassium alloys, are useful as catalysts in the coupling of ethylenically-unsaturated hydrocarbons with aromatic hydrocarbons having an active hydrogen on a saturated alpha-carbon. The supported alkali metals are more effective than the corresponding unsupported alkali metals in such reactions but are still not as effective as might be desired.
Claff et al., Journal of Organic Chemistry, Vol. 20, pp. 20 440-442 and 981-986 (1955) disclose the use of sodium oxide in the metalation of toluene by potassium; and the speculative teachings of U. S. Pat. No. 3,691,242 (Cheng et al.) include the substitution of an alkali metal oxide for an alkali metal alkoxide as a cc-catalyst in the alkali metal-catalyzed reaction of cumene with ethylene or propylene.
Copending application Ser. No. 356,186 (Smith), filed May 24, 1989, discloses the use of an oxide of sodium, potassium, or rubidium as a co-catalyst for the coupling of ethene and/or propene with aromatic hydrocarbons having an active hydrogen on a saturated .alpha.-carbon in the presence of a supported alkali metal as a catalyst.